Adjustable drawing die



March 11 1969 KIYOSHI HAJIKANO 3,431,769

ADJUSTABLE DRAWING DIE Filed Oct. 5, 1966 Sheet 0f 4 20|7I8 23 Ill March 1969 KIYOSHI HAJIKANO 3,431,769

ADJUSTABLE DRAWING DIE Filed Oct. 5, 1966 Sheet 2 of 4 mImIIIIII."

FIGJO. FIGJI. FIG.|2.

March 11, 1969 KVIYOSHI HAJIKANO 3,431,759

ADJUSTABLE DRAWING DIE Filed Oct. 5, 1966 Sheet 3 March 19169 KIYOSHI HAJIKANO 3,431,769

ADJUSTABLE DRAWING DIE Filed Oct. 5, 1966 Sheet of 4 ll H3 FIQJS.

United States Patent Olfice 3,431,769 Patented Mar. 11, 1969 61,347 US. Cl. 72468 Int. Cl. B21c 3/ 06';B21d 3/00 Claims ABSTRACT OF THE DISCLOSURE An adjustable drawing die in which a plurality of cylindrical rolls are pivotably mounted at their ends in a pair of supporting members which are rotatably and axially displaceable relative to one another, the rolls being arranged in an annular array around the axis of their supporting members to cooperatively define a surface bounding an internal die opening such that as said members are relatively displaced, the surface defined by the rolls can be varied between an initial surface which is cylindrical or conical and hyperboloidal surfaces with various size die openings. The support members can be locked, to in turn lock the rolls in their particular positions, and the support members can be driven in rotation thereby to rotate the rolls.

This invention concerns, particularly, a roll-type drawing die including a pair of roll supporting rings arranged co-axially to each other and a plurality of rolls supported by said roll supporting rings to cooperatively define an opening constitutting a die nozzle which has a hyperboloid surface composed of inner matrix lines of said rolls.

In hitherto known methods for drawing bars or pipes by dies, usually several dies of different sizes are used to draw material into products. Therefore, the standard rate of reducing cross-sectional area for each drawing is definite, and suitable heat treatment is carried out during the drawing process. At least several, and sometimes more than ten drawing steps using dies of different sizes are adopted.

Especially, in the case of precision drawing many more dies of different sizes are used. Accordingly in the conventional drawing operation, many dies of different sizes are required.

If the die angle, or the angle in the die hole (throttle angle) is small, then the contact area between material and die is large, so that the frictional resistance becomes large. And if the die angle is large, then deformation occurs abruptly and the deformation resistance becomes large. Therefore it is known that the optimum angle must be therebetween, and this optimum die angle becomes larger in proportion to increase of the reducing rate of the cross-section. Therefore, it is necessary that the die having optimum die angle be selected according to drawing conditions, for example, materials to be drawn, so that many kinds of dies are required from this view point.

Of course, much expense is necessary to satisfy the requirements stated above.

Moreover, in all known dies, no openings are provided on the throttling or reducing surface of the hole die, that is, the surface is closed, so that it is impossible to supply sufficient lubricant on the surface. However, friction resistance during drawing is very large. Further if any cracks may occur in the surface of the die hole, the sur face must be cut off to correct the die hole, or the die would not be able to be utilized, and the size of the die would become larger because of such correction.

The present invention aims to eliminate those disadvantages described above and to provide advantages which will be described later.

According to the present invention, there is provided an adjustable drawing die comprising a pair of supporting cylinders, spaced and arranged coaxially to each other, a pair of roll supporting rings disposed between said cylinders, each being secured to a respective cylinder, a plurality of cylindrical rolls having opposite ends supported in said rings and arranged in an annular array around the axis of said supporting cylinders to cooperatively define a surface bounding an internal die opening, means pivotably mounting said ends of the rolls in said rings to enable the rolls to be tilted relative to the rings as the latter are rotated relative to one another whereby the surface defined by the rolls can be varied between a cylindrical surface and hyperbol'oidal surfaces with various size die openings, a pair of inner rings between the roll supporting rings each being detachably secured to a respective roll supporting ring, a key on the outer circumference of one inner ring, the other inner ring having a tapered circumferential surface, an outer ring having a keyway receiving said key and a tapered surface facing the tapered outer circumferential surface of said other inner ring, a tightening cylinder slidably fitted on said one inner ring, threads on the inside circumference of said outer ring and on the outer circumference of the tightening cylinder, said threads being engaged with each other to enable the inner ring and thereby the rolls to be locked in position by turning of the tightening cylinder, and means for rotating the outer ring to cause the locked rolls to rotate therewith about the axis of the supporting cylinders.

In a modification, the adjustable drawing die comprises two spaced frames including respective ring-shaped portions in coaxially spaced, opposed relation, a plurality of cylindrical rolls having opposite ends supported in said ring-shaped portions and arranged in an annular array around the axis of said ring-shaped portions to cooperatively define a surface bounding an internal die opening, means supporting the frames for relative angular and axial movement, means pivotably mounting said ends of the rolls in said ring-shaped portions to enable the rolls to be tilted relative to the ring-shaped portions as the frames are angularly rotated and axially displaced whereby the surface defined by the rolls can be varied between a truncated conical surface and hyperboloidal surfaces with various size die openings, and means for rotating the frames and the rolls therewith about the axis of the ring-shaped portions.

The invention is explained by way of examples in the following description in conjunction with the attached drawings.

FIG. 1 is a side view of a first embodiment of a drawing die in which the upper half is broken away and only one roll is shown;

FIG. 2 is an end view of half of the left inner wheel;

FIG. 3 is a side view of the ring of FIG. 2, with the upper half broken away and shown in longitudinal section;

FIG. 4 is an end view of half of the right inner ring;

FIG. 5 is a side view of the ring of FIG. 4, with the upper half broken away and shown in longitudinal section;

FIG. 6 is an end view of half of the outer ring;

FIG. 7 is a front view of the ring of FIG. 6, with the upper half broken away and shown in longitudinal section;

FIG. 8 is a side view of a key;

FIG. 9 is an end view of half of a roll supporting ring;

FIG. 10 is an end view of a cover for the left roll supporting ring;

FIG. 11 is a side view of the cover FIG. 10, with the upper half broken away and shown in longitudinal section;

FIG. 12 is an end view of half of a cover for the right roll supporting ring;

FIG. 13 is a diagrammatic side view of the rolls illustr-at the principles of the present invention;

FIG. 14 is an end view of the rolls of FIG. 13;

FIG. 15 is a side view of a modified embodiment of the die with the upper half broken away and shown in section;

FIG. 16 is a diagrammatic side view of the rolls in FIG. 15 for illustrating the principle of the die shown in FIG. 15; and

FIG. 17 is an end view of the rolls of FIG. 16.

Referring to the drawings, an embodiment of the present invention includes a pair of roll supporting cylinders 1, 2. Extending outwardly from cylindrical parts 3, 4 of the cylinders there are provided flanges 5, 6. The supporting cylinders are arranged c-o-axially to each other. A roll supporting ring 7, a roll supporting wheel cover 9 and a left inner wheel 11 are arranged at the inside of flange 5 of left supporting cylinder 1; while a roll sup porting ring 8, a roll supporting ring cover and a right inner ring 12 are arranged at the inside of flange 6 of right supporting cylinder 2. The roll supporting rings 7 and 8 are provided respectively with sixteen bearings 13, 14 which are arranged and equally spaced on the same circle. Said bearings 13 and 14 are disposed in opposed relation to each other with suitable spacing.

The left inner ring 11 has a flange 16 which extends outwardly from cylindrical part 15. The flange supports key 17, secured with threads 18, at its circumference. A tightening cylinder 19 is slidably fitted on the outside of the cylindrical part 15. At the outside of the tightening cylinder 19, is a thread 20 and four holes as provided for inserting a handle to turn cylinder 19. The right inner ring 12 has a cylindrical part 22 from which extends an outwards flange 23 having a taper portion 24 on its outer circumference. The flange 16 of left inner wheel 11 and the flange 23 of right inner ring 12 are opposed each other.

An outer wheel 25 consists of a cylindrical part 26 and a flange 27 which extends inwardly therefrom. At the inner surface of the cylindrical part 26, thread 28 engages with the thread 20 of said tightening cylinder 19, and key grooves engage key 17, of left inner ring 15. At the inner surface of the flange 27 of the outer wheel 25, a taper portion 30 engages the taper portion 24 of said right inner wheel 12. A gear 31 is provided at the outer circumference of outer wheel 25.

Spherical bearing elements 35, 36 are provided at necks 33, 34 at each end of each roll 32 of cylindrical form. Said bearing elements are supported in the bearings 13, 14 of the roll supporting 7, 8. Snap rings 37, 38 engage spherical bearing members 35, 36 at opposite ends of each roll and shaft collars 39, 40 are secured on the necks 33, 34. Each roll 32 is rotatably mounted at its ends and the rolls 32 are arranged in a cylindrical array. Six bolts 41 and two knockpins (not shown) pass from the left side of left flange 5 through roll supporting ring 7, roll supporting Wheel cover 9 and are inserted or screwed into cylindrical part 15 of left inner ring 11, to fix said flange 5, roll supporting wheel 7, roll supporting ring cover 9 and left inner ring 11. Two knock-pins 42 and six bolts 41 (not shown) pass from the right side of right flange 6 through roll supporting ring '8, roll supporting ring cover 10 and are inserted or screwed into cylindrical part 22 of right inner ring 12 to fix said flange 6, roll supporting ring 8, roll supporting cover 10 and right inner ring 12.

Three other bolts 43 are screwed into the inner ring 12 from the right side of the ring 12.

Cylindrical parts 3, 4 of supporting cylinders 1, 2 are supported by roller bearings 44, 45 and a flange 5 of left supporting cylinder 1 is supported by a thrust bearing 46.

Gear 31 of the outer wheel 25 is engaged with another gear 47 and driven by a motor (not shown). Thrust bearings 48, 49 are provided at the foot of neck 33, 34 of both ends of each roll 32. Needle roller bearings 50, 51 are provided between spherical bearing elements 35.

When the three bolts 43 of inner ring 12 are screwed to a disengaged position and inner rings 11, .12 are rotated in relatively opposite direction, then all the rolls 32 incline from their axial positions, and the distance between inner rings 11, 12 decreases, the left inner wheel 11 sliding towards outer wheel .25 by the engagement of key 17 in key groove 29 in axial direction, while the right inner wheel can rotate relative to the outer wheel 25 due to the taper surfaces 24 and 30.

Thereafter, the three bolts 43 are advanced into the right inner ring 12 by being screwed to the left. Thereby the tip of the bolt contacts the right side of the flange 16 of the left inner ring 11. Then a suitable handle (not shown) is inserted into a hole 21 of tightening cylinder 19 to rotate the tightening cylinder 19, and to screw the tightening cylinder into outer Wheel 25. This causes the right and left inner rings 11, 12 to be fixed against the outer wheel 25 by the tightening cylinder 19, the three bolts 43 and the taper surfaces 24, 30 whereby each roll 32 is locked in the inclined position.

When the outer wheel 25 is rotated by gears 47, 31 by a motor (not shown), the rolls 32 rotate around the center shaft of said supporting cylinder 1, 2 in the inclined position as described above.

FIG. 13 and FIG. 14 show illustrative views of inclined positions 1-1, 2-2', 2-2 16-16 of the sixteen r-olls 32.

As seen from these drawings When the cylindrical rolls 32 are axially oriented, they cooperatively define a surface bounding an internal opening of cylindrical form. When the rolls 32 are inclined by relative rotation of support rings 7, 8, they cooperatively define a hyperboloidal surface as shown in dotted line in FIG. 13. The die hole according to the present invention is formed by the hyperboloidal surface as defined by the rolls 32. The size of the die corresponds to a diameter of a circle (FIG. 13) which is internally tangent each roll in said inclined positions 1-1, 2-2, 3-3' 16-16'.

When material is inserted into the hole of the hyperboloidal surface formed by the rolls, and drawn from the rotating die, a desired drawing operation will be completed.

As clearly understood from the description hitherto, according to the present invention, the inclination of each of rolls can be changed freely, thereby the form of the hyperboloidal surface can be changed and therefore the size of the die can be also changeable while the die angle can be also changeable. Therefore the many kinds of dies as required by the prior art are not required.

Also according to the present invention, we can obtain a die which has any size and any die angles by selecting two of three elements or all of the three elements which are length, number and diameter of rolls.

In addition, sufiicient lubricant can be supplied through clearances between each of rolls because the throttling surfaces of the die hole or contacting surface between the die and the material to be worked consists of a plurality of rolls. Additionally, only a very small frictional resistance is encountered so that the power required for drawing is decreased because the rolls are rotated around the material during drawing. This also minimizes the chances for causing cracks, because each of rolls revolves around its axis as it rotates around the material and the large circumferential surface of the cylindrical part of each of the rolls can contact with the material. Even if cracks may occur in a roll then it can be replaced individually which is advantageous from an economical point of view.

According to the present invention, inner rings are provided at the supporting rings of the rolls, and a key and a taper surface are provided on these inner rings, respectively engaged with a key way and a taper surface formed on an outer ring, the tightening cylinder being revolvable to adjust the orientation of the rolls and therefore the shape and size of the die opening by merely turning a handle. From the construction described above, the present invention makes it possible to control the inclination of each roll easily and maintain the position of each roll uniformly and securely.

Another embodiment of the invention will be explained herein-below with reference to FIGS. 15, 16 and 17 of the accompanying drawings. In FIGURE 15, numerals 101 and 102 designate left and right frames having at their ends ring-shaped portions 103 and 104 which are spaced from each other in an opposed concentric relation. The left frame 101 has a cylindrical part 105 connected to the ring-shaped portion 103, said cylindrical part 105 being provided with stepped portions 106 and 107 in succession. Likewise, the right-side frame 102 has a cylindrical part 108 connected to the ring-shaped portion 104, with said part 108 being provided with a stepped portion 109. The cylindrical part 105 of frame 101 and the corresponding cylindrical part 108 of frame 102 are disposed in slidably engaged relation with each other, while the stepped portion 106 of the cylindrical part 105 is opposed to an end face 110 of the cylindrical part 108 and the stepped portion 107 of the cylindrical part 106 is opposed to the stepped portion 109 of the cylindrical part 107. Between the stepped portions 107 and 109 is interposed compression spring 111-. Both frames 101 and 102 are received in a cylindrical die receiving housing 112. At the left end of the die receiving housing 112 is a. flange 113 against which is abutted the ring-shaped portion 103 of the frame 101. Several screw rods 114 are inserted from the outside at the left side of the flange 113 into the ring-shaped portion 103, thereby to secure the frame 101 to the die receiving housing 112. At the right side on the inner face of the cylindrical part of the die receiving housing 112 is an internal thread 115 into which is screwed a ring screw 116 thereby to hold in position the right-side face of the frame 102. There are also provided several screw rods 117 which are driven from the flange 113 at the left end of the die receiving box housing through the cylindrical part 105 and the stepped portion 106 of the frame 101, with their ends reaching the end face 110 of the cylindrical part 108 of the frame 102, so that the frame 102 is secured in position by the screwing operation of said screw rods 117 and of the ring screw 116. After movement of the ring screw 116 to the right to a disengaged position, the frame 102 while being pushed by the compression springs 111, is rotated and at the same time moved rightward and then the screw rods 117 are screwed in to advance to the right until their ends reach the end face 110 of the cylindrical part 108, thereby fixing the frame 102 in position. Alternatively, after movement to the left of the screw rods 117, the frame 102, against the force of the compression springs 111, is rotated and moved leftwards and then the ring screw 116 is screwed in and moved to the left, whereby it is also possible to fix the frame 102 in position.

In the opposing inner faces of the ring-shaped portions 103 and 104 of frames 101 and 102, respectively, are provided a plurality of substantially semicircular recesses 119 which rotatably support the ends 120 of a plurality of rolls 118. The recesses 119 are provided at equal intervals therebetween along a circle centered around the central axis of the ring-shaped portions 103 and 104. The diameter of the circle at the position where the recesses 119 are provided in the ring-shaped portion 103 at the left side is smaller than that at the position where the recesses 119 are provided in the ring-shaped portion 104 at right side. Both ends 120 of a plurality of rolls 118 are shaped substantially semicircularly so as to be snugly received in the recesses 119. Said rolls 118, when arranged in axial planes define a truncated cone. The rolls can be tilted in the ring-shaped portions 103 and 104 and they may rotate individually. There is formed a recessed section 121 near the substantially semi-circular end of each roll so that when the roll is tilted, the cylindrical side face of the roll does not contact the ring-shaped portion.

In the above-described arrangement, when the left frame 101 is secured to the die receiving housing 112 by means of the screw rods 114 and the'right frame 102 is rotated, said frame 102 and its ring-shaped portion 104 are accordingly moved either to the right or left along the central axis thereof since the rolls 118 are supported between the right and left ring-shaped portions 104 and 103. In other words, the rotation and the rightward or leftward movement of the frame 102 and the ring-shaped portion 104 are attained by an amount corresponding to the degree of inclination of the rolls 118, while the rolls 118 are maintained in such position that the rolls do not fall out of the ring-shaped portions 103 and 104.

There are provided clutch plates 122 at several positions in the die receiving housing 112 so that, after the positions of the frames 101 and 102 have been fixed, the frame 102 may be secured to the die receiving housing 112. The clutch plates 122 are arranged in such manner that their inner faces may contact the cylindrical part 108 of the frame 102 and that they may be operated by the screw rods 123.

By loosening or fastening the screw rods 123, the pressure between the clutch plates 122 and the cylindrical part 108 of frame 102 is adjusted so as to effect mounting or dismounting of the frame 102 into or from the die receiving housing 112.

The die receiving housing 112 is rotatably supported by roller bearings 124 so that it may rotate around its central axis. The die receiving housing 112 is also so arranged as to be fixed (for example key-checked) in the center hole of a gear 125 which is arranged to be driven through another gear 126 by a motor (not shown).

The structure of the die of the present invention will be illustrated hereinafter in more detail. As described above, the frame 102 is rotated and concurrently moved to the right or left in relation to the frame 101 and the rolls 118 are thereby tilted in the ring-shaped portions 103' and 104. When a desired tilted position of the rolls is reached, the frames 101 and 102 are fixed in position by means of the screw rods 117 and the ring screw 116 while said frames 101 and 102 are secured to the die receiving housing 112 by screw rods 114 and clutch plates 122, respectively. Thereafter, the die receiving box 112 is driven in rotation through gears 125 and 126 and accordingly frames 101 and 102 rotate. These operations result in rotating rolls 118 around the central axis of ring-shaped portions 103 and 104 while maintaining said rolls in tilted positions. In the illustrative FIGURES 16 and 17, the tilted positions of rolls 118 are indicated by numerals 11, 2-2', 3-3 1212. As will be understood from these figures, the rolls 118 approach a central axis (corresponding to the line 0-0 in FIGURES l6 and 17) as the angle of inclination of rolls 118 decreases. It will thus be seen that the inner surfaces of the cylindrical side faces of rolls 118 confronting said central axis form a .hyperboloidal surface as indicated by the dotted lines in FIG- URE 16. The contour of the nozzle of the die is formed by the hyperboloidal surface, and the size of die corresponds to the diameter of a circle inscribed in the lines 1-1, 2-2 1212'. A circle formed by connecting the points where the left ends 120 of rolls 118 are supported in the ring-shaped portion 103 has a smaller diameter than a circle formed by connecting the points where the right ends 120 are supported in the ring-shaped portion 104. Namely, since the rolls 118 are arranged to define a truncated cone, an area where the diameter of the hyperboloidal surface is smallest (the part corresponding to the inscribed circle in FIGURE 17) is situated closer to the ring-shaped portion 103 than to the center point between the ring-shaped portions 103 and 104 (said area is displaced to the left as shown in FIGURE 16).

Thus, when the molding material is fed into the nozzle of the die formed by said hyperboloidal surface and advanced from right to left (during which the die is rotating), the material is subjected to the desired drawing process in accordance with the nozzle in the hyperboloidal surface. It will be noted that in this case the effective contact area between the material and the nozzle is extremely great. In other words, the effective diaphragm area is larger in the case where the rolls 118 are arranged axially to define a truncated cone than in the case where they are simply arranged in parallel to define cylinder as in the previous embodiment.

As will be evident from the foregoing explanation with the die of the present invention, it is possible to optionally change the amount of rotation and rightwise or leftwise movement of the ring-shaped portion 103 in relation to the ring-shaped portion 104, and the change in amount of rotation and movement results in change in shape of the hyperboloidal surface, thus permitting optional change in the size of the die. It is also possible to freely change the die-angle, thus eliminating any necessity of providing a variety of dies as in the conventional devices. Also, by changing one, or two or all of the three factors, i.e., length, number and diameter of the rolls, it is possible to produce a die having various sizes and die-angles. Further, since the nozzle of the die, namely the contact face with the material, of the present invention is composed of a plurality of rolls, it is possible to supply lubricating oil through the spaces between the rolls. Still further, the drawing process is conducted while effecting rotation of the rolls around the material, which greatly reduces the frictional resistance as compared with the conventional process and thus requires much smaller tensile strength for achieving the desired drawing. Since each of the rolls rotates around the material and also around its own axis, a wide circumferential face of the cylindrical part of each roll contacts the material, thus reducing the possibility of producing cracks in the rolls. In case cracks do appear on a roll, one has only to replace the cracked roll, which is greatly simplified as compared to the conventional devices thereby providing economical advantage. In addition, the present invention has the feature of an extremely wide efifective reducing area of the nozzle as compared with the size of the die.

What is claimed is:

1. An adjustable drawing die comprising a pair of supporting cylinders, spaced and arranged coaxially to each other, a pair of roll supporting rings disposed between said cylinders, each being secured to a respective cylinder, a plurality of cylindrical rolls having opposite ends supported in said rings and arranged in an annular array around the axis of said supporting cylinders to cooperatively define a surface bounding an internal die opening, means pivotably mounting said ends of the rolls in said rings to enable the rolls to be tilted relative to the rings as the latter are rotated relative to one another whereby the surface defined by the rolls can be varied between a cylindrical surface and hyperboloidal surfaces with various size die openings, a pair of inner rings between the roll supporting rings each being detachably secured to a respective roll supporting ring, a key on the outer circumference of one inner ring, the other inner ring having a tapered circumferential surface, an outer ring having a keyway receiving said key and a tapered surface facing the tapered outer circumferential surface of said other inner ring, a tightening cylinder slidably fitted on said one inner ring, threads on the inside circumference of said outer ring and on the outer circumference of the tightening cylinder, said threads being engaged with each other to enable the inner ring and thereby the rolls to be locked in position by turning of the tightening cylinder, and means for rotating the outer ring to cause the locked rolls to rotate therewith about the axis of the supporting cylinders.

2. An adjustable drawing die comprising two spaced frames including respective ring-shaped portions in coaxially spaced, opposed relation, a plurality of cylindrical rolls having opposite ends supported in said ring-shaped portions and arranged in an annular array around the axis of said ring-shaped portions to cooperatively define a surface bounding an internal die opening, means supporting the frames for relative angular and axial movement, means pivotably mounting said ends of the rolls in said ring-shaped portions to enable the rolls to be tilted relative to the ring-shaped portions as the frames are angularly rotated and axially displaced whereb the surface defined by the rolls can be varied between hyperboloidal surfaces with various size die openings, and means for rotating the frames and the rolls therewith about the axis of the ring-shaped portions.

3. An adjustable die as claimed in claim 2 wherein said means pivotably mounting the ends of said rolls in said ring-shaped portions comprises ball-shaped portions on said ends of said rolls, and recesses provided in said ringshaped portions receiving said ball-shaped portions.

4. An adjustable die as claimed in claim 2 comprising a spring interposed between said frames urging the same axially apart, a threaded rod threadably engaged in one frame and extending therefrom towards the other frame for contacting the same, and an axially adjustabe member engageable with said other frame on a side thereof opposite said threaded rod to lock said other frame in position.

5. An adjustable die as claimed in claim 2 wherein said means for rotating the frames comprises a housing which can be driven in rotation receiving said frames, and means for securing the frames to said housing for rotation therewith.

References Cited UNITED STATES PATENTS MILTON S. MEHR, Primary Examiner.

US. Cl. X.R. 72-78 

